FBI Director James Comey defended his disclosure decisions related to the FBI investigation into Hillary Clinton's email server, but he also told senators, "It makes me mildly nauseous to think that we had an impact on the election."

Though Comey was testifying on oversight issues before the Judiciary Committee, much of the questioning centered around the FBI's investigation into Russian meddling in the presidential election and about Clinton's private server. Under questioning by ranking member Sen. Dianne Feinstein, D-California, Comey recalled what went into his decision to tell Congress on Oct. 28, 11 days before the election, that the FBI was investigating Clinton, having already announced the probe into Clinton had ended in July.

On Oct. 27, Comey said he had met with investigators who said they could see thousands of emails from the Clinton email domain, and they said they thought they needed a search warrant to look at those. At this point, Comey explained that there were thousands of emails missing from the first three months of Clinton's tenure as secretary of State, and there was some question about whether these emails, discovered on the laptop of top Clinton aide Huma Abedin's husband, Anthony Weiner, might be the missing emails.

"It was an incredibly painful choice but actually not all that hard -- between very bad and catastrophic," Comey recollected. "I had to tell Congress that we were taking these additional steps - I prayed to find a third door, I couldn't find it. Two actions: speak or conceal? I don't think many reasonable people would do it differently than I did no matter what they say today. If you were standing there staring at that on Oct 28 would you really conceal that?"

One staffer had asked him whether or not he should consider that what he was going to do could help Donald Trump win the presidency. But he said he had not for a moment considered it, "because down that path lies the death of the FBI." At the end of their debate, Comey said that "everyone on my team agreed we have to tell Congress that we are restarting this in a hugely significant way."

The FBI found thousands of emails, including a "lot of new stuff," but nothing changed their view of Clinton's intent, Comey said.

His testimony came after a day after Clinton again placed some of the blame on him for her loss to Donald Trump in the 2016 presidential election.

Comey also told senators of his struggle to decide whether to speak openly about the outcome of the Clinton investigation in July 2016. It would ordinarily be announced by the Justice Department, Comey said. But he felt that then-Attorney General Loretta Lynch's tarmac meeting with former President Bill Clinton made that impossible. "The department cannot by itself, credibly end this," Comey told the senators.

"The best chance we have in the justice system is if I do something I never imagined before: step away from them and tell the American people, 'Look, here's what the FBI did, here's what we found, here's what we think,' and that offered us the best chance of the American people believing in the system," Comey said. He went on to say, "That was a hard call for me to make to call the attorney general that morning and say, 'I'm about to do a press conference, and I'm not going to tell you what I'm going to say.' And I said to her, 'I hope one day you'll understand why I have to do this.'"

Comey said he "knew it would be disastrous for me personally, but I thought this is the best way to protect these institutions we care so much about."

South Carolina Sen. Lindsey Graham asked Comey about former acting Attorney General Sally Yates, who informed the White House that she believed Mr. Trump's national security adviser, Michael Flynn had been compromised by Russian intelligence. Comey said that he had spoken with Yates on the topic, but he did not elaborate in the open hearing.

Under questioning, he also declined confirm whether there is an active investigation into the leaking of classified information related to President Trump or his associates. Comey also said it was possible that a special prosecutor would be recommended to lead the Russia investigation.

Follow below for our live blog during the hearing.

1:44p.m. Comey says "it's possible" that a special prosecutor would be recommended to lead the investigation when asked by Sen. Richard Blumenthal, Blumenthal hopes Comey will argue forcefully and vigorously for a special prosecutor.

1:33 p.m. Franken said it was a "shame" that Cornyn suggested that Clinton blamed everyone but herself during the Tuesday event. She did take responsibility, too, for the mistakes in her campaign.

1:14 p.m. Sen. Patrick Leahy, D-Vermont, points out that President Trump's threat to block all Muslims from the U.S. is still on his campaign website today. Leahy asked Comey if this threatens the U.S., and Comey said he didn't want to address his specific statement, but he said that targeting of various groups, including Muslims, makes the FBI's job harder.

1:01 p.m. Comey said that more technology companies are understanding the need to protect public safety compared to the need to protect privacy.

12:36 p.m. Comey said that he's been interviewed by the inspector general about his actions in the course of what he suggested was the Clinton email investigation.

"I don't have any regrets," he said.

Blumenthal asked Comey if he believes universal background checks are important to prevent gun violence. Comey said that from the perspective of law enforcement, more information is always helpful to keep guns out of the hands of criminals.

12:30 p.m. Sen. Richard Blumenthal, D-Connecticut, asked Comey if he can rule out people from the Trump campaign, including the president, from the investigation into the Trump campaign and possible collusion with Russia. Comey said that he didn't want to reveal anyone because then it would lead down a slippery slope toward who they're targeting. He said he briefed Grassley and Feinstein on who is being investigated.

12:18 p.m. In an exchange with Sen. Mazie Hirono, D-Hawaii, Comey said he was not concerned about the political ramifications of his decision to speak about the restarted investigation into Clinton's emails last October.

"I find that hard to believe that you did not contemplate that there would be political ramifications to your comments," Hirono said.

Comey said that he knew there would a "huge storm" that would come.

12:04 p.m. Coons said that Comey had a third door available to him ahead of the election, and that was that there was an investigation into the Trump campaign and Russian interference. Comey rejected that idea and said that he wouldn't want to confirm an investigation in its early stages, but that he did call out the Russians for its attempt to mess with the U.S. election.

12:01 p.m. Sen. Chris Coons, D-Delaware, asked what the U.S. can do to protect against its elections in the future. Comey said that the government should tell election officials what techniques Russians can use and to equip the American people and allies that this is even going on, amid all of the Russian propaganda.

11:54 a.m. Comey is describing "incidental collection" whereby a terrorist outside the U.S. could be discovered if that person is in touch with an American.

Sen. Jeff Flake, R-Arizona, asked what the FBI is doing to protect its own systems amid the threat of data breaches. Comey said a "whole lot," but he doesn't want to get into specifics.

"A ton of work has gone into protecting our systems," Comey said, but the weak link are the people.

Comey said that Congress could do more to protect its systems.

"I'm sure that Congress's is not good enough," he said.

11:48 a.m. Sen. Al Franken, D-Minnesota, asked Comey about why Russia favored Donald Trump in the 2016 election. Comey said that Russian President Vladimir Putin "hated" Hillary Clinton and that he preferred a businessman like Trump to make deals rather than Clinton who spent much of her life in politics.

11:38 a.m. Sen. Ben Sasse, R-Neb., asked how likely is it that the Senate IT system has been targeted by foreign adversaries.

"I would estimate it's a certainty," Comey said.

Speaking about WikiLeaks, Comey said he couldn't confirm whether there are charges pending against Julian Assange and that he has sought refuge in the Ecuadorian embassy.

11:21 a.m. Sen. Lindsey Graham, R-South Carolina, asked if he agrees that if sequestration goes back into effect in the next fiscal year, it would be devastating to the FBI. Comey agreed.

Graham asked if he ever spoke to Sally Yates about Gen. Michael Flynn being compromised. Comey said she did, but that he wasn't sure he could elaborate in a public setting.

Comey said he can't say whether Fusion is part of the Russian intelligence apparatus. Graham said that someone should be prosecuted for allowing Anthony Weiner to have access to classified information.

Comey agreed that it's fair to say that Russia actively provides safe haven to cyber criminals and that Russia should still pay a price for interfering in the U.S. political system.

"In my view, the greatest threat of any nation on earth given their intention and capability," Comey said, describing Russia.

Comey said that "it's fair" to say that Russia could eventually be capable of changing vote tallies if the U.S. doesn't stop them.

11:07 a.m. Sen. John Cornyn, R-Texas, said it was unfortunate that Clinton blamed Comey for her election loss during an event a day earlier. Speaking about 702, Comey said that "really bad" people around the world use devices and infrastructure built by the U.S. and that 702 allows the FBI to immediately track these people in terrorism cases.

11:02 a.m. Comey said that he expects the FBI won't make "a peep" about the investigation into Russia's meddling in the election until they finish the probe. Comey reiterated that the FBI has "high confidence" that North Korea hacked into SONY and that Russia hacked into the Democratic National Committee (DNC).

10:46 a.m. Feinstein said that most people have looked at this investigation and have concluded that the FBI did affect the outcome of the election. After lawyers raised the concern that he could help one of the candidates win, Comey said that he couldn't consider that because it would kill the independence of the FBI.

Comey: FBI's impact on election makes him "mildly nauseous"

10:41 a.m. Feinstein asked Comey why it was necessary for him to announce 11 days before the election that he was announcing a new investigation on Oct. 28. On Oct. 27, Comey said he met with investigators who said they can see thousands of emails from the Clinton email domain and they said they think they needed a search warrant to look at those. Then he said, he faced a choice.

Comey said that he saw two doors that said "speak" and the other said "conceal." To restart in a "hugely significant way," Comey said that it would be "catastrophic" to conceal the restarted investigation but "really bad" to speak before the election.

He said his team found thousands of emails, including a "lot of new stuff," but nothing changed their view of Clinton's intent.

"This was terrible," Comey said. "It makes me mildly nauseous to think that we had an impact on the election."

10:38 a.m. Comey said that the shadow created by the problem of "going dark" is affecting about half of the FBI's work. He said that half of the devices the FBI encounters in terrorism cases, gang-related cases and child pornography cases cannot be opened with any technique.

Comey said there continues to be a "huge collision" between privacy and public safety.

10:33 a.m. Grassley asked Comey if he has ever been an anonymous source in the Trump investigation or Clinton investigation.

"Never," Comey said, adding that he has never authorized anyone else to be an anonymous source.

Grassley asked if there's an investigation into the leaking of any classified information relating to Trump or his associates. Comey said he doesn't want to answer that question.

"I don't want to confirm in an open setting whether there are any investigations open," Comey said.

Grassley asked what the difference is between this case and the Valerie Plame case, and Comey said he doesn't have the authority.

10:28 a.m. Comey has begun his opening statement and he said that oversight of the FBI is "essential" by having people ask hard questions. He said he appreciates the conversation about reauthorizing FISA Section 702 authority. He said the program is "essential."

"If it goes away, we will be less safe as a country," Comey said.

He also spoke about the threats faced by Jewish Community Centers throughout the first half of the year.

Comey said he "loves this work" and "I love this job."

10:22 a.m. Sen. Dianne Feinstein, D-California, the top Democrat on the panel, began her opening statement and called Comey's letter to Congress on Oct. 28 about new emails found related to the investigation into Hillary Clinton's use of a private email server an "October surprise." The FBI concluded that the emails found on a computer owned by Anthony Weiner did not warrant any new charges or any new investigation.

Feinstein said lawmakers need to hear how the FBI will regain the trust of Congress and the American public.

10:00 a.m.ET The hearing has begun and Sen. Chuck Grassley, R-Iowa, the chairman of the panel, has been talking about the election and Russia's interference in the election as well as FBI's efforts to thwart terror attacks in the U.S.

"Unfortunately, the FBI has provided me materially inconsistent information about these issues. That is why we need to know more about it and how much the FBI relied on it. Once you buy into its claims of collusion, then suddenly every interaction with a Russian can be twisted to seem like confirmation of the conspiracy theory," Grassley said.

"Now, obviously I don't know what the FBI will find. For the good of the country, I hope that the FBI gets to the truth soon, whatever that may be. If there are wrongdoers, they should be punished. And the innocent should have their names cleared. In the meantime, this Committee is charged with oversight of the FBI, and we can't wait until this is all over to ask the hard questions. Otherwise, too many people will have no confidence in the FBI's conclusions."